Want to expand a genome? Previous thinking suggests you only need some transposable elements, often nicknamed “jumping genes”, to repeatedly, and irreversibly, insert into the genome. Time will take care of the rest. However, new research is now challenging this view by revealing that transposable elements can also be deleted during evolution. The new findings were recently reported by Louie van de Lagemaat, Dixie Mager and their colleagues from the Terry Fox Laboratory in Vancouver, BC. They compared the human, chimpanzee and Rhesus monkey genomes and found 37 instances where transposable elements were present in the primitive Rhesus monkey, but…